The flowing gas laser employing a gas such as CO.sub.2 or a mixture of gases, such as CO.sub.2, He, CO, H.sub.2 and N.sub.2, as the lasing medium is capable of continuously generating high power, e.g., power of 200 watts and above. A major problem in obtaining high power output from that type of laser is the tendency of the electric discharge in the lasing medium to arc. A high power electric glow discharge in the high velocity gas flowing through the lasing region is difficult to maintain because of instabilities that adversely affect the electric discharge. Those instabilities cause or contribute to the breakdown of the diffuse uniform glow discharge that occurs in the proper operation of the laser into arcs. Arcing severely reduces lasing efficiency and causes a breakdown of the lasing medium so that the conditions for the proper electric field current density and gain uniformity are not achieved. Arcing can also harm the laser by damaging the electrodes and other structures in the region of the arc. The propensity of the lasing medium to arc increases as the input power loading is increased, and the instabilities accompanying the dynamics of gas flow at high velocities can contribute to the tendency of the electric discharge in the lasing medium to change from the glow mode into the unwanted arc mode.
The "prior art" technical literature pertaining to high power, flowing gas lasers specifically discloses arrangements for the deliberate introduction of turbulence in the gas flow for the purpose of "smoothing" or "spreading" the current to prevent arcing in the electric discharge of the gas lasing medium. See, for example, the monograph titled "Closed-Cylce Performance Of A High-Power Electric Discharge Laser" by Brown and Davis in Appl. Phys. Lett., Vol. 21, No. 10, Nov. 15, 1972, and U.S. Pat. Nos. 3,772,610 and 4,016,448.
The large scale, high intensity turbulence utilized in "prior art" high power, flowing gas lasers, while effectively enabling greater input power loading without arcing in the electric glow discharge, tends to degrade other desirable properties of the gas flow. Large scale, high intensity turbulence, for example, tends to degrade homogeneity of the gas, and distort the acoustic spectrum. In addition to other undesired effects, that turbulence interferes with the isolation of the gas from contact with the channel walls provided by what otherwise would be undisturbed wall boundary layers and that turbulence can degrade the ability to recover a sizable fraction of the gas flow field's dynamic pressure. Also, the introduction of turbulence into the gas flow generally requires a pressure drop in the flow loop which must be compensated for by the use of larger or more powerful blowers.